Energy efficient OLED TV

ABSTRACT

Embodiments of the disclosed subject matter provide a full-color pixel arrangement for a device, the full-color pixel arrangement including a plurality of sub-pixels, each having an emissive region of a first color, where the full-color pixel arrangement comprises emissive regions having exactly one emissive color that is a red-shifted color of a deep blue sub-pixel of the plurality of sub-pixels. Embodiments of the disclosed subject matter may also provide a full-color pixel arrangement for a device, the full-color pixel arrangement including a plurality of sub-pixels, each having an emissive region of a first color, where the full-color pixel arrangement comprises emissive regions having exactly one emissive color, and where the plurality of sub-pixels comprise a light blue sub-pixel, a deep blue sub-pixel, a red sub-pixel, and a green sub-pixel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No.62/702,932, filed Jul. 25, 2018, the entire contents of which areincorporated herein by reference.

FIELD

The present invention relates to providing a full color display thatincludes an unpatterned light blue phosposrescent organic light emittingdiode (OLED), that includes deep blue sub-pixels enabled by filtering ormicrocavity design, as well as other colored sub-pixels that may beenabled by filtering, cavity design, or downconversion light blue. Thelight blue unpatterned OLED may be in a stacked arrangement, and mayinclude phosphorescent and/or fluorescent and/or electroluminescentquantum dot emissive layers.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting diodes/devices (OLEDs), organic phototransistors, organicphotovoltaic cells, and organic photodetectors. For OLEDs, the organicmaterials may have performance advantages over conventional materials.For example, the wavelength at which an organic emissive layer emitslight may generally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Alternatively the OLED can be designed to emit white light. Inconventional liquid crystal displays emission from a white backlight isfiltered using absorption filters to produce red, green and blueemission. The same technique can also be used with OLEDs. The white OLEDcan be either a single EML device or a stack structure. Color may bemeasured using CIE coordinates, which are well known to the art.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processible” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

SUMMARY

According to an embodiment, an organic light emitting diode/device(OLED) is also provided. The OLED can include an anode, a cathode, andan organic layer, disposed between the anode and the cathode. Accordingto an embodiment, the organic light emitting device is incorporated intoone or more device selected from a consumer product, an electroniccomponent module, and/or a lighting panel.

According to an embodiment, a full-color pixel arrangement for a devicemay be provided, the full-color pixel arrangement including a pluralityof sub-pixels, each having an emissive region of a first color, wherethe full-color pixel arrangement comprises emissive regions havingexactly one emissive color that is a red-shifted color of a deep bluesub-pixel of the plurality of sub-pixels.

The exactly one emissive color may be light blue having a peakwavelength which may be greater than or equal to 460 nm, greater than orequal to 465 nm, or greater than or equal to 470 nm. The exactly oneemissive color may be light blue having 1931 CIE coordinates with CIEythat is greater than or equal to 0.20, greater than or equal to 0.15, orgreater than or equal to 0.10. The exactly one emissive color may beformed by a phosphorescent light blue emitter.

The plurality of sub-pixels of the full-color pixel arrangement mayinclude a light blue sub-pixel, the deep blue sub-pixel, a redsub-pixel, and a green sub-pixel. The deep blue sub-pixel may be formedby applying a color change medium to the light-blue sub-pixel, and has aresultant color range of 1931 CIE coordinates with CIE y of less than0.10. The deep blue sub-pixel may be disposed in a microcavity to blueshift an output of the emissive region. The red light from the redsub-pixel and green light from the green sub-pixel may be generated bydown-converting light emitted from the emissive color of the emissiveregions by photoemissive quantum dots that are part of the red sub-pixeland the green sub-pixel. At least one of the red sub-pixels and thegreen sub-pixels uses a color filter to refine a spectrum of at leastone of the red light emitted from the red subpixel and the green lightemitted from the green sub-pixel. At least one of the light bluesub-pixel and the deep blue sub-pixel may be formed in a cavitystructure. At least one of the light blue sub-pixel and the deep bluesub-pixel may be formed using a non-cavity structure. The emissiveregions having exactly one emissive color may be a single emissive layerincluding one emitter, a single emissive layer having a plurality ofemitters, or a stacked emissive layer device. Each emissive layer of thestacked emissive layer device may have the same type of emitters, has acombination of types of emitters, or has different types of emitters.The emissive layers in the stacked emissive layer device may include alight blue phosphorescent emitter and a deep blue fluorescent emitter.The emissive layers in the stacked emissive layer device may include alight blue phosphorescent emitter and a green phosphorescent emitter.The pixel arrangement may include a yellow sub-pixel. The full-colorpixel arrangement of the device may include a white sub-pixel. Theemissive regions having exactly one emissive color may bephosphorescent, and are used to generate light emitted by the whitesub-pixel. The deep blue sub-pixel of the pixel arrangement may beshared by a plurality of pixels.

The full-color pixel arrangement may provide a Rec2020 color gamut. Thedevice having the full-color pixel arrangement may be anelectroluminescent quantum dot device.

According to an embodiment, a full-color pixel arrangement for a devicemay be provided, the full-color pixel arrangement may include aplurality of sub-pixels, each having an emissive region of a firstcolor, where the full-color pixel arrangement comprises emissive regionshaving exactly one emissive color, and where the plurality of sub-pixelscomprise a light blue sub-pixel, a deep blue sub-pixel, a red sub-pixel,and a green sub-pixel.

The exactly one emissive color may be light blue having a peakwavelength that may be greater than or equal to 460 nm, greater than orequal to 465 nm, and greater than or equal to 470 nm. The exactly oneemissive color may be light blue having 1931 CIE coordinates with CIEygreater than or equal to 0.20, greater than or equal to 0.15, or greaterthan or equal to 0.10. The exactly one emissive color is formed by aphosphorescent light blue emitter.

The deep blue sub-pixel of the full-color pixel arrangement may beformed by applying a color change medium to the light-blue sub-pixel,and may have a resultant color range of 1931 CIE coordinates with CIE yof less than 0.10. The deep blue sub-pixel may be disposed in amicrocavity to blue shift an output of the emissive region.

Red light from the red sub-pixel and green light from the greensub-pixel may be generated by down-converting light emitted from theemissive color of the emissive regions by photoemissive quantum dotsthat are part of the red sub-pixel and the green sub-pixel. At least oneof the red sub-pixels and the green sub-pixels uses a color filter torefine a spectrum of at least one of the red light emitted from the redsubpixel and the green light emitted from the green sub-pixel.

At least one of the light blue sub-pixel and the deep blue sub-pixel maybe formed in a cavity structure. At least one of the light bluesub-pixel and the deep blue sub-pixel may be formed using a non-cavitystructure.

The emissive regions having exactly one emissive color may be a singleemissive layer including one emitter, a single emissive layer having aplurality of emitters, or a stacked emissive layer device. Each emissivelayer of the stacked emissive layer device may have the same type ofemitters, may have a combination of types of emitters, or may havedifferent types of emitters. The emissive layers in the stacked emissivelayer device may include a light blue phosphorescent emitter and a deepblue fluorescent emitter. The emissive layers in the stacked emissivelayer device include a light blue phosphorescent emitter and a greenphosphorescent emitter. The pixel arrangement may include a yellowsub-pixel.

The pixel arrangement may include a white sub-pixel. The emissiveregions having exactly one emissive color may be phosphorescent, and maybe used to generate light emitted by the white sub-pixel. The deep bluesub-pixel of the pixel arrangement may be shared by a plurality ofpixels.

The pixel arrangement may provide a Rec2020 color gamut. The device maybe an electroluminescent quantum dot device.

In an embodiment, a full-color pixel arrangement for an organic lightemitting diode (OLED) device may be provided, the full-color pixelarrangement including a plurality of sub-pixels, each having an emissiveregion of a first color, where the full-color pixel arrangementcomprises emissive regions having exactly two emissive colors.

The exact two emissive colors may be light blue and deep blue. Theemissive regions may be a phosphorescent emissive layer, a fluorescentemissive layer, or a thermally activated delayed fluorescent (TADF)layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIG. 3 shows an example of a pixel layout showing an unpatterned lightblue OLED that includes deep blue, red, and green sub-pixels that areprovided by filtering, cavity design, or downconversion according toembodiments of the disclosed subject matter.

FIG. 4 shows an example of a pixel layout showing an unpatterned lightblue OLED with deep blue, red, and green sub-pixels that are provided byfiltering, cavity design, or downconversion, where each deep bluesub-pixel is shared by at least one other pixel according to embodimentsof the disclosed subject matter.

FIG. 5 shows a sub-pixel layout for a RGBY (Red-Green-Blue-Yellow)display using one OLED deposition (e.g., light blue) to provide aRGYB1B2 architecture, where B1 and B2 may be light blue and deep bluesub-pixels according to embodiments of the disclosed subject matter.

FIG. 6 shows an example of a pixel layout showing an unpatterned warmwhite OLED with warm white, deep blue, light blue, red, and greensub-pixels provided by filtering, cavity design, or downconversion,where each deep blue sub-pixel is shared by at least one other pixelaccording to embodiments of the disclosed subject matter.

DETAILED DESCRIPTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), are incorporated byreference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, a cathode 160, and a barrier layer 170.Cathode 160 is a compound cathode having a first conductive layer 162and a second conductive layer 164. Device 100 may be fabricated bydepositing the layers described, in order. The properties and functionsof these various layers, as well as example materials, are described inmore detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which areincorporated by reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Emissive layers, such as emissive layer 135 and emissive layer 220 shownin FIGS. 1-2 respectively, may include quantum dots. An “emissive layer”or “emissive material” as disclosed herein may include an organicemissive material and/or an emissive material that contains quantum dotsor equivalent structures, unless indicated to the contrary explicitly orby context according to the understanding of one of skill in the art.Such an emissive layer may include only a quantum dot material whichconverts light emitted by a separate emissive material or other emitter,or it may also include the separate emissive material or other emitter,or it may emit light itself directly from the application of an electriccurrent. Similarly, a color altering layer, color filter, upconversion,or downconversion layer or structure may include a material containingquantum dots, though such layer may not be considered an “emissivelayer” as disclosed herein. In general, an “emissive layer” or materialis one that emits an initial light, which may be altered by anotherlayer such as a color filter or other color altering layer that does notitself emit an initial light within the device, but may re-emit alteredlight of a different spectra content based upon initial light emitted bythe emissive layer.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. Pat. No. 7,431,968, which is incorporated by reference in itsentirety. Other suitable deposition methods include spin coating andother solution based processes. Solution based processes are preferablycarried out in nitrogen or an inert atmosphere. For the other layers,preferred methods include thermal evaporation. Preferred patterningmethods include deposition through a mask, cold welding such asdescribed in U.S. Pat. Nos. 6,294,398 and 6,468,819, which areincorporated by reference in their entireties, and patterning associatedwith some of the deposition methods such as ink-jet and OVJD. Othermethods may also be used. The materials to be deposited may be modifiedto make them compatible with a particular deposition method. Forexample, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processibility than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the presentinvention may further optionally comprise a barrier layer. One purposeof the barrier layer is to protect the electrodes and organic layersfrom damaging exposure to harmful species in the environment includingmoisture, vapor and/or gases, etc. The barrier layer may be depositedover, under or next to a substrate, an electrode, or over any otherparts of a device including an edge. The barrier layer may comprise asingle layer, or multiple layers. The barrier layer may be formed byvarious known chemical vapor deposition techniques and may includecompositions having a single phase as well as compositions havingmultiple phases. Any suitable material or combination of materials maybe used for the barrier layer. The barrier layer may incorporate aninorganic or an organic compound or both. The preferred barrier layercomprises a mixture of a polymeric material and a non-polymeric materialas described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporatedby reference in their entireties. To be considered a “mixture”, theaforesaid polymeric and non-polymeric materials comprising the barrierlayer should be deposited under the same reaction conditions and/or atthe same time. The weight ratio of polymeric to non-polymeric materialmay be in the range of 95:5 to 5:95. The polymeric material and thenon-polymeric material may be created from the same precursor material.In one example, the mixture of a polymeric material and a non-polymericmaterial consists essentially of polymeric silicon and inorganicsilicon.

Devices fabricated in accordance with embodiments of the invention canbe incorporated into a wide variety of electronic component modules (orunits) that can be incorporated into a variety of electronic products orintermediate components. Examples of such electronic products orintermediate components include display screens, lighting devices suchas discrete light source devices or lighting panels, etc. that can beutilized by the end-user product manufacturers. Such electroniccomponent modules can optionally include the driving electronics and/orpower source(s). Devices fabricated in accordance with embodiments ofthe invention can be incorporated into a wide variety of consumerproducts that have one or more of the electronic component modules (orunits) incorporated therein. A consumer product comprising an OLED thatincludes the compound of the present disclosure in the organic layer inthe OLED is disclosed. Such consumer products would include any kind ofproducts that include one or more light source(s) and/or one or more ofsome type of visual displays. Some examples of such consumer productsinclude flat panel displays, computer monitors, medical monitors,televisions, billboards, lights for interior or exterior illuminationand/or signaling, heads-up displays, fully or partially transparentdisplays, flexible displays, laser printers, telephones, mobile phones,tablets, phablets, personal digital assistants (PDAs), wearable devices,laptop computers, digital cameras, camcorders, viewfinders,micro-displays (displays that are less than 2 inches diagonal), 3-Ddisplays, virtual reality or augmented reality displays, vehicles, videowalls comprising multiple displays tiled together, theater or stadiumscreen, and a sign. Various control mechanisms may be used to controldevices fabricated in accordance with the present invention, includingpassive matrix and active matrix. Many of the devices are intended foruse in a temperature range comfortable to humans, such as 18 C to 30 C,and more preferably at room temperature (20-25 C), but could be usedoutside this temperature range, for example, from −-40 C to 80 C.

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

In some embodiments, the OLED has one or more characteristics selectedfrom the group consisting of being flexible, being rollable, beingfoldable, being stretchable, and being curved. In some embodiments, theOLED is transparent or semi-transparent. In some embodiments, the OLEDfurther comprises a layer comprising carbon nanotubes.

In some embodiments, the OLED further comprises a layer comprising adelayed fluorescent emitter. In some embodiments, the OLED comprises aRGB pixel arrangement or white plus color filter pixel arrangement. Insome embodiments, the OLED is a mobile device, a hand held device, or awearable device. In some embodiments, the OLED is a display panel havingless than 10 inch diagonal or 50 square inch area. In some embodiments,the OLED is a display panel having at least 10 inch diagonal or 50square inch area. In some embodiments, the OLED is a lighting panel.

In some embodiments of the emissive region, the emissive region furthercomprises a host.

In some embodiments, the compound can be an emissive dopant. In someembodiments, the compound can produce emissions via phosphorescence,fluorescence, thermally activated delayed fluorescence, i.e., TADF (alsoreferred to as E-type delayed fluorescence), triplet-tripletannihilation, or combinations of these processes.

The OLED disclosed herein can be incorporated into one or more of aconsumer product, an electronic component module, and a lighting panel.The organic layer can be an emissive layer and the compound can be anemissive dopant in some embodiments, while the compound can be anon-emissive dopant in other embodiments.

The organic layer can also include a host. In some embodiments, two ormore hosts are preferred. In some embodiments, the hosts used maybe a)bipolar, b) electron transporting, c) hole transporting or d) wide bandgap materials that play little role in charge transport. In someembodiments, the host can include a metal complex. The host can be aninorganic compound.

Combination with Other Materials

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identify othermaterials that may be useful in combination.

Various materials may be used for the various emissive and non-emissivelayers and arrangements disclosed herein. Examples of suitable materialsare disclosed in U.S. Patent Application Publication No. 2017/0229663,which is incorporated by reference in its entirety.

Conductivity Dopants:

A charge transport layer can be doped with conductivity dopants tosubstantially alter its density of charge carriers, which will in turnalter its conductivity. The conductivity is increased by generatingcharge carriers in the matrix material, and depending on the type ofdopant, a change in the Fermi level of the semiconductor may also beachieved. Hole-transporting layer can be doped by p-type conductivitydopants and n-type conductivity dopants are used in theelectron-transporting layer.

HIL/HTL:

A hole injecting/transporting material to be used in the presentinvention is not particularly limited, and any compound may be used aslong as the compound is typically used as a hole injecting/transportingmaterial.

EBL:

An electron blocking layer (EBL) may be used to reduce the number ofelectrons and/or excitons that leave the emissive layer. The presence ofsuch a blocking layer in a device may result in substantially higherefficiencies, and or longer lifetime, as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the EBLmaterial has a higher LUMO (closer to the vacuum level) and/or highertriplet energy than the emitter closest to the EBL interface. In someembodiments, the EBL material has a higher LUMO (closer to the vacuumlevel) and or higher triplet energy than one or more of the hostsclosest to the EBL interface. In one aspect, the compound used in EBLcontains the same molecule or the same functional groups used as one ofthe hosts described below.

Host:

The light emitting layer of the organic EL device of the presentinvention preferably contains at least a metal complex as light emittingmaterial, and may contain a host material using the metal complex as adopant material. Examples of the host material are not particularlylimited, and any metal complexes or organic compounds may be used aslong as the triplet energy of the host is larger than that of thedopant. Any host material may be used with any dopant so long as thetriplet criteria is satisfied.

HBL:

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies and/or longer lifetime as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the HBLmaterial has a lower HOMO (further from the vacuum level) and or highertriplet energy than the emitter closest to the HBL interface. In someembodiments, the HBL material has a lower HOMO (further from the vacuumlevel) and or higher triplet energy than one or more of the hostsclosest to the HBL interface.

ETL:

An electron transport layer (ETL) may include a material capable oftransporting electrons. The electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

Charge Generation Layer (CGL)

In tandem or stacked OLEDs, the CGL plays an essential role in theperformance, which is composed of an n-doped layer and a p-doped layerfor injection of electrons and holes, respectively. Electrons and holesare supplied from the CGL and electrodes. The consumed electrons andholes in the CGL are refilled by the electrons and holes injected fromthe cathode and anode, respectively; then, the bipolar currents reach asteady state gradually. Typical CGL materials include n and pconductivity dopants used in the transport layers.

OLED displays, such as for television, have desirable performancecharacteristics over other types of displays. It is desirable tocontinue to improve the performance of OLED displays, and reduce theircost. Some current large area OLED displays use patterning of organicmaterials at the pixel level to avoid color filters, which makesfabrication from large area substrates more difficult. Some othercurrent large area OLEDs may have reduced performance from not beingable to use highly efficient (e.g., phosphorescent) blue sub-pixels.

It is desirable to make OLED TVs without the need for pixel patterningof the OLED films, and to benefit from the high efficiency offered byphosphorescent OLEDs. Current OLED TVs rely on the use of a whiteunpatterned OLED stack, with color filters used to produce deep blue,green, and red sub-pixels. Others have proposed an approach to make OLEDTVs based on an unpatterned deep blue OLED deposition, with quantum dotdown-conversion to provide red and green sub-pixels. Although both ofthese approaches benefit from not having any deposition of the organicmaterial through a fine metal mask (FMM) to render the pixel patterning,both of these approached have low efficiency deep fluorescent blue, asthe lifetime of the high efficiency phosphorescent deep blue does notyet meet commercial requirements.

Embodiments of the disclosed subject matter provide a full color OLEDdisplay architecture using light blue and deep blue sub-pixels to enablean unpatterned (at the pixel level) highly efficient light bluephosphorescent OLED or TADF (thermally activated delayed fluorescence)OLED to be deposited unpatterned over a large area substrate. Deep bluesub-pixels may be formed by filtering or with a microcavity design fromthe light blue emissive layer, and red, green, and/or yellow sub-pixelsmay be provided by patterning quantum dots to downconvert the light blueOLED. That is, embodiments of the disclosed subject matter provide anOLED display architecture that includes a highly efficient lightphosphorescent blue as the unpatterned OLED emissive layer, and thatincludes a B1B2 architecture to provide for deep blue sub-pixels. In thepresence of light blue sub-pixels, deep blue sub-pixels may be used fora small fraction of the time, i.e., when a color may not be renderedfrom the light blue sub-pixel emission. This arrangement reduces thelifetime requirement for the deep blue sub-pixel. Moreover, theunpatterned light blue sub-pixel can take advantage of a highfill-factor, as pixel layout in this arrangement may not have large OLEDdeposition alignment tolerances between sub-pixels (i.e., preventing onecolor emitter being placed in an adjacent color sub-pixel). Inembodiments of the disclosed subject matter, sub-pixels may be definedby lithography and/or color filter or down conversion medium patterning.

For a deep blue sub-pixel, current light blue phosphorescent emittersmay have an onset that begins below 450 nm. Using the B1B2 architecturedescribed throughout, deep blue emission may be used for a smallfraction (e.g., less than 5%) of common images, so the photons presentin the spectrum tail of light blue emitters from 450-460 nm may be usedto generate deep blue sub-pixels. This can be accomplished either byusing a color filter to remove longer wavelengths from the light blueemission, or by placing the deep blue sub-pixel in a microcavity toremove the longer wavelengths from the light blue emission.

In some embodiments, a stacked blue unpatterned OLED may be used toprovide a sufficient deep blue component. The stacked blue unpatternedOLED may be combined in the same overall stacked or tandem device thatincludes a deep blue emissive layer. The deep blue emissive layer may bepreferably fluorescent, but phosphorescent emitters may be used (e.g.,when lifetime is improved), with one or more light blue phosphorescent,fluorescent, or TADF emissive layers.

For red and green sub-pixels, down conversion from light blue to greenand red may be accomplished by photoemissive quantum dots. These aregenerally applied using solution processed deposition techniques eitheron top of an encapsulated OLED stack, or may be patterned on a coversheet aligned to a backplane or frontplane of a device. Ink jetprinting, stamping, and/or other patterning techniques may be used toform the quantum dot sub-pixels.

FIG. 3 shows one embodiment of the disclosed subject matter, where anunpatterned light blue OLED is used as the OLED emissive stack. Inparticular, FIG. 3 shows a sub-pixel layout for an RGB display with oneOLED deposition of light blue emissive material that may enable theRGB1B2 architecture that includes light blue and deep blue sub-pixels.That is, FIG. 3 shows an example of a pixel arrangement having anunpatterned light blue OLED with deep blue, red, and green sub-pixelsthat may be enabled by filtering, cavity design, or downconversion.

Sub-pixel rendering may be used to allow one deep blue sub-pixel to beshared by at least one other pixel. FIG. 4 shows an example of a pixelarrangement having an unpatterned light blue OLED with deep blue, red,and green sub-pixels that may be enabled by filtering, cavity design, ordownconversion. That is, FIG. 4 shows a sub-pixel layout for a displayusing one OLED deposition of light blue that enables the RGB1B2architecture having light blue and deep blue sub-pixels. Each deep bluesub-pixel may be shared by at least one other pixel. For example, FIG. 4shows that four pixels share a deep blue sub-pixel. This may improve thefill factor of the deep blue sub-pixels, and may reduce the number ofpixel driver circuits and external data driver chips. This arrangementmay enable 3.25 sub-pixels per pixel instead of 4 sub-pixels per pixel,as shown in FIG. 3. The display shown in FIG. 4 may have four colors,including red, green, light blue, and deep blue.

Light blue and deep blue sub-pixels may be formed in either structureshaving a cavity, or non-cavity structures, and they need not be thesame. One color of B1 or B2 could use a cavity design while the othercolor may not use a cavity design. In some embodiments, both B1 and B2may use a cavity design or, in some other embodiments, both use anon-cavity design.

The OLED emissive layer (EML) may be a single EML device, or a stackeddevice. Each EML in a stacked device may have the same emitter orcombination of emitters, or may use different emitters. For example, oneEML in a stacked OLED may be light blue phosphorescent and a second EMLmay be a deeper blue fluorescent EML to provide a greater deep bluecomponent for the deep blue sub-pixels.

A four sub-pixel display may provide an increased color gamut than aconventional 3sub-pixel display and may provide an improved path to aRec2020 color gamut. Photoemissive quantum dots may provide saturatedred and green sub-pixels. By using the B1B2 architecture describedthroughout, the deep blue B2 may be more saturated than can be realizedin a single blue sub-pixel display. That is, the single blue deep blueOLED sub-pixel may not be as efficient and have a reduced lifetimecompared to the B1B2 architecture.

The B1B2 architecture may be used in conjunction with OLED devices basedon different emission principles such as TADF, hyperfluorescence, orphosphor sensitized fluorescence.

To achieve Rec2020 color, a plurality of photons with a peak wavelengthof about 640 nm may be used to achieve a saturated red of approximately(0.69, 0.31). The red sub-pixel may be the largest sub-pixel in anarrangement where all sub-pixels have similar lifetime. In embodimentsof the disclosed subject matter, sub-pixels may be based on a light blueOLED, independent of the color of the light emitted from that sub-pixel.One way to reduce the usage of the deep red sub-pixel and to extend itslifetime may be to add a yellow sub-pixel to each pixel. In this case,most images around the white point of the CIE chart may be rendered withblue and yellow, and a small amount of deep saturated green and deepsaturated red may be used to render colors towards the red and greenvertices of the CIE chart. This architecture is shown in FIG. 5.

FIG. 5 shows a sub-pixel arrangement for RGBY (red, green, blue, yellow)displays using a light blue OLED deposition, and enabling the RGB1B2architecture according to an embodiment of the disclosed subject matter.As shown in FIG. 5, one dark blue sub-pixel may be used for every fourpixels. This is merely an example, and the one dark blue sub- pixel maybe shared with at least one other pixel. The arrangement shown in FIG. 5may reduce the number of TFT circuits and data lines to 4.25 per pixel.A display formed from the arrangement shown in FIG. 5 may have 5 colors,including red, green, yellow, light blue, and deep blue.

In one embodiment, a full color OLED display based on only a light blueunpatterned OLED deposition, where each pixel has at least 4 colors,with two different color blue sub-pixels. The deep blue sub-pixel sharedamongst a plurality of pixels. In some embodiments, the light blueunpatterned OLED may be in a stacked arrangement, and may include bothphosphorescent and fluorescent emissive layers. Photoemissive quantumdots may be used to downconvert light blue emitted by the light blueunpatterned OLED to green and/or red to form green and/or redsub-pixels. A full color display based on light emission from one OLEDemissive stack that provides Rec2020 color gamut. The full color displaymay include pixels that may have red, green, yellow, light blue, anddeep blue sub-pixels. Some embodiments may include fluorescent andphosphorescent emitters or a TADF emitter in a stacked arrangement or ina tandem blue OLED.

In some embodiments of the disclosed subject matter, a high efficiencyOLED display may be formed using an unpatterned OLED deposition. Insteadof a conventional OLED display utilizing a cool white (e.g., D65)unpatterned OLED which relies on low efficiency fluorescent blue as acomponent to make white, embodiments of the disclosed subject matter mayuse a warm white OLED deposition (e.g., D30) such that phosphorescentlight blue may be used in a white stack, instead of deep fluorescentblue. This arrangement may produce the warmer white color. A deep bluesub-pixel may be added using the techniques described above, where thedeep blue sub-pixel may be used to produce a D65 white point. As shownin FIG. 6, this arrangement may produce a display having five colors ineach pixel, including warm white, light blue, deep blue, green, and red,with 4.25 sub-pixels per pixel.

FIG. 6 shows an example of a pixel layout having an unpatterned warmwhite OLED with deep blue, light blue, red, and green sub-pixels enabledby filtering, cavity design, or downconversion, where each deep bluesub-pixel may be shared by at least one other pixel. A sub-pixelarrangement may be for a display using a warm white OLED deposition thatenables the RGB1B2 architecture having one light blue and one deep bluesub-pixel. As shown in FIG. 6, one dark blue sub-pixel may be used forevery four pixels. This is merely an example, and the one dark sub-pixelmay be used with at least one other pixel. This arrangement may reducethe number of TFT circuits and data lines to 4.25 per pixel.

In the embodiments described above in connection with FIGS. 3-6, afull-color pixel arrangement for a device may be provided, thefull-color pixel arrangement including a plurality of sub-pixels, eachhaving an emissive region of a first color, where the full-color pixelarrangement comprises emissive regions having exactly one emissive colorthat is a red-shifted color of a deep blue sub-pixel of the plurality ofsub-pixels. The exactly one emissive color may be light blue having apeak wavelength which may be greater than or equal to 460 nm, greaterthan or equal to 465 nm, or greater than or equal to 470 nm. In someembodiments, the exactly one emissive color may be light blue having1931 CIE coordinates with CIEy that is greater than or equal to 0.20,greater than or equal to 0.15, or greater than or equal to 0.10. Theexactly one emissive color may be formed by a phosphorescent light blueemitter. The exactly one emissive color may be formed by a TADF emitterand/or phosphor sensitized fluorescence.

The plurality of sub-pixels of the full-color pixel arrangement mayinclude a light blue sub-pixel, the deep blue sub-pixel, a redsub-pixel, and a green sub-pixel. The deep blue sub-pixel may be formedby applying a color change medium to the light-blue sub-pixel, and has aresultant color range of 1931 CIE coordinates with CIE y of less than0.10. The deep blue sub-pixel may be disposed in a microcavity to blueshift an output of the emissive region.

The red light from the red sub-pixel and green light from the greensub-pixel may be generated by down-converting light emitted from theemissive color of the emissive regions by photoemissive quantum dotsthat are part of the red sub-pixel and the green sub-pixel. At least oneof the red sub-pixels and the green sub-pixels uses a color filter torefine a spectrum of at least one of the red light emitted from the redsubpixel and the green light emitted from the green sub-pixel. At leastone of the light blue sub-pixel and the deep blue sub-pixel may beformed in a cavity structure and/or may be formed using a non-cavitystructure.

The emissive regions of the device having exactly one emissive color maybe a single emissive layer including one emitter, a single emissivelayer having a plurality of emitters, or a stacked emissive layerdevice. Each emissive layer of the stacked emissive layer device mayhave the same type of emitters, a combination of types of emitters, ordifferent types of emitters. The emissive layers in the stacked emissivelayer device include a light blue phosphorescent emitter and a deep bluefluorescent emitter. In some implementations, the emissive layers in thestacked emissive layer device include a light blue phosphorescentemitter and a green phosphorescent emitter.

The pixel arrangement of the device may include a yellow sub-pixel. Insome embodiments, the full-color pixel arrangement of the device mayinclude a white sub-pixel. The emissive regions having exactly oneemissive color may be phosphorescent, and are used to generate lightemitted by the white sub-pixel. The deep blue sub-pixel of the pixelarrangement may be shared by a plurality of pixels. For example, thedeep blue-sub-pixel may be shared by 2 pixels, 4 pixels, or the like.

Is some embodiments, the full-color pixel arrangement of the device mayprovide a Rec2020 color gamut. The device having the full-color pixelarrangement may be an electroluminescent quantum dot device.

According to an embodiment of the disclosed subject matter, a full-colorpixel arrangement for a device may be provided, the full-color pixelarrangement may include a plurality of sub-pixels, each having anemissive region of a first color, where the full-color pixel arrangementcomprises emissive regions having exactly one emissive color, and wherethe plurality of sub-pixels comprise a light blue sub-pixel, a deep bluesub-pixel, a red sub-pixel, and a green sub-pixel.

The exactly one emissive color may be light blue having a peakwavelength that may be greater than or equal to 460 nm, greater than orequal to 465 nm, and greater than or equal to 470 nm. In someembodiments, the exactly one emissive color may be light blue having1931 CIE coordinates with CIEy greater than or equal to 0.20, greaterthan or equal to 0.15, or greater than or equal to 0.10. The exactly oneemissive color is formed by a phosphorescent light blue emitter. In someembodiments, the exactly one emissive color can be formed by a TADFemitter and/or phosphor sensitized fluorescence.

The deep blue sub-pixel of the full-color pixel arrangement may beformed by applying a color change medium to the light-blue sub-pixel,and may have a resultant color range of 1931 CIE coordinates with CIE yof less than 0.10. The deep blue sub-pixel may be disposed in amicrocavity to blue shift an output of the emissive region.

Red light from the red sub-pixel and green light from the greensub-pixel may be generated by down-converting light emitted from theemissive color of the emissive regions by photoemissive quantum dotsthat are part of the red sub-pixel and the green sub-pixel. At least oneof the red sub-pixels and the green sub-pixels uses a color filter torefine a spectrum of at least one of the red light emitted from the redsubpixel and the green light emitted from the green sub-pixel.

At least one of the light blue sub-pixel and the deep blue sub-pixel maybe formed in a cavity structure. At least one of the light bluesub-pixel and the deep blue sub-pixel may be formed using a non-cavitystructure.

The emissive regions of the device having exactly one emissive color maybe a single emissive layer including one emitter, a single emissivelayer having a plurality of emitters, or a stacked emissive layerdevice. Each layer of the stacked emissive layer device may have thesame type of emitters, may have a combination of types of emitters, ormay have different types of emitters. The emissive layers in the stackedemissive layer device may include a light blue phosphorescent emitterand a deep blue fluorescent emitter. The emissive layers in the stackedemissive layer device may include a light blue phosphorescent emitterand a green phosphorescent emitter. The pixel arrangement may include ayellow sub-pixel.

The pixel arrangement of the device may include a white sub-pixel. Insome embodiments, the emissive regions having exactly one emissive colormay be phosphorescent, and may be used to generate light emitted by thewhite sub-pixel. The deep blue sub-pixel of the pixel arrangement may beshared by a plurality of pixels.

The pixel arrangement may provide a Rec2020 color gamut. The device maybe an electroluminescent quantum dot device.

In an embodiment of the disclosed subject matter, a full-color pixelarrangement for an OLED device may be provided, the full-color pixelarrangement including a plurality of sub-pixels, each having an emissiveregion of a first color, where the full-color pixel arrangementcomprises emissive regions having exactly two emissive colors. The exacttwo emissive colors may be light blue and deep blue. The emissiveregions may be a phosphorescent emissive layer, a fluorescent emissivelayer, or a thermally activated delayed fluorescent (TADF) layer.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

1. A full-color pixel arrangement for a device, the full-color pixelarrangement comprising: a plurality of sub-pixels, each having anemissive region of a first color, wherein the full-color pixelarrangement comprises emissive regions having exactly one emissive colorthat is a red-shifted color of a deep blue sub-pixel of the plurality ofsub-pixels.
 2. The full-color pixel arrangement of claim 1, wherein theexactly one emissive color is light blue having a peak wavelengthselected from the group consisting of: greater than or equal to 460 nm,greater than or equal to 465 nm, and greater than or equal to 470 nm. 3.The full-color pixel arrangement of claim 1, wherein the exactly oneemissive color is light blue having 1931 CIE coordinates with CIEyselected from the group consisting of: greater than or equal to 0.20,greater than or equal to 0.15, and greater than or equal to 0.10.
 4. Thefull-color pixel arrangement of claim 1, wherein the exactly oneemissive color is formed by a phosphorescent light blue emitter.
 5. Thefull-color pixel arrangement of claim 1, wherein the plurality ofsub-pixels comprise: a light blue sub-pixel, the deep blue sub-pixel, ared sub-pixel, and a green sub-pixel.
 6. The full-color pixelarrangement of claim 5, wherein the deep blue sub-pixel is formed byapplying a color change medium to the light-blue sub-pixel, and has aresultant color range of 1931 CIE coordinates with CIE y of less than0.10.
 7. The full-color pixel arrangement of claim 5, wherein the deepblue sub-pixel is disposed in a microcavity to blue shift an output ofthe emissive region.
 8. The full-color pixel arrangement of claim 5,wherein red light from the red sub-pixel and green light from the greensub-pixel are generated by down-converting light emitted from theemissive color of the emissive regions by photoemissive quantum dotsthat are part of the red sub-pixel and the green sub-pixel. 9.(canceled)
 10. The full-color pixel arrangement of claim 5, wherein atleast one of the light blue sub-pixel and the deep blue sub-pixel areformed in a cavity structure.
 11. (canceled)
 12. The full-color pixelarrangement of claim 5, wherein the emissive regions having exactly oneemissive color are selected from the group consisting of: a singleemissive layer including one emitter, a single emissive layer having aplurality of emitters, and a stacked emissive layer device.
 13. Thefull-color pixel arrangement of claim 12, wherein each emissive layer ofthe stacked emissive layer device has the same type of emitters, acombination of types of emitters, or different types of emitters. 14.-18. (canceled)
 19. The full-color pixel arrangement of claim 5, whereinthe deep blue sub-pixel of the pixel arrangement is shared by aplurality of pixels.
 20. (canceled)
 21. The full-color pixel arrangementof claim 1, wherein the device is an electroluminescent quantum dotdevice.
 22. A full-color pixel arrangement for a device, the full-colorpixel arrangement comprising: a plurality of sub-pixels, each having anemissive region of a first color, wherein the full-color pixelarrangement comprises emissive regions having exactly one emissivecolor, and wherein the plurality of sub-pixels comprise a light bluesub-pixel, a deep blue sub-pixel, a red sub-pixel, and a greensub-pixel.
 23. The full-color pixel arrangement of claim 22, wherein theexactly one emissive color is light blue having a peak wavelengthselected from the group consisting of: greater than or equal to 460 nm,greater than or equal to 465 nm, and greater than or equal to 470 nm.24. The full-color pixel arrangement of claim 22, wherein the exactlyone emissive color is light blue having 1931 CIE coordinates with CIEyselected from the group consisting of: greater than or equal to 0.20,greater than or equal to 0.15, and greater than or equal to 0.10. 25.(canceled)
 26. The full-color pixel arrangement of claim 22, wherein thedeep blue sub-pixel is formed by applying a color change medium to thelight-blue sub-pixel, and has a resultant color range of 1931 CIEcoordinates with CIE y of less than 0.10.
 27. (canceled)
 28. Thefull-color pixel arrangement of claim 22, wherein red light from the redsub-pixel and green light from the green sub-pixel are generated bydown-converting light emitted from the emissive color of the emissiveregions by photoemissive quantum dots that are part of the red sub-pixeland the green sub-pixel. 29.-41. (canceled)
 42. A full-color pixelarrangement for an organic light emitting diode (OLED) device, thefull-color pixel arrangement comprising: a plurality of sub-pixels, eachhaving an emissive region of a first color. wherein the full-color pixelarrangement comprises emissive regions having exactly two emissivecolors.
 43. The full-color pixel arrangement of claim 42, wherein theexact two emissive colors are light blue and deep blue.
 44. (canceled)